- Quantification of intraplaque neovascularization on CEUS imaging: Following the infusion of ultrasound contrast agent, the presence of blood flow "activity" will be identified based on the dynamic movement of the echogenic reflectors (microbubbles) observed within the intraplaque microvessels. Intraplaque neovascularization (contrast-agent enhancement) will be categorized with visual interpretation using a grading scale previously published: Grade 1 will be used to indicate no appearance of moving bubbles within the plaque or microspheres only confined to the adjacent adventitial layer, Grade 2 will be considered for moderate visible appearance of moving bubbles within the plaque at the adventitial side or plaque shoulder, and Grade 3 will be reserved for images with extensive intraplaque neovascularization with clear visible appearance of bubbles moving to the plaque core.